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Full text of "Report on the ENIAC (Electronic numerical integrator and computer)"

Report on 

THE ENIAC 

{Electronic Numerical Integrator and Computer) 



Developed under the supervision of the 
Ordnance Department, United States Army 



OPERATING MANUAL 



UNIVERSITY OF PENNSYLVANIA 
Moore School of Electrical Engineering 

PHILADELPHIA, PENNSYLVANIA 

June h 1946 



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A REPORT ON THE EIJIAG 
(Electronic Numerical Integrator and Computer) 



■Report of i^ork under Contract No, 1Y-670-0RD-4926 



BoGween 



Ordnancg_ perartniont y. United States Army 
7/ashingto n, P ., Cj»_ 

and 

^j?_ho^ Un Ivors it y of . PGnnsy.^ X^Alg; 

Moor p_ Schoo l of Elect rical E ngin eering 

Philadelphia, Pa, 



This is copy No. ;l9 
of 25 bound copies of 
this report. 






ENIAC OPMATIMG MANUAL 

by 

Dr, Arthur V/,, Burks 

and 
Dr, Plarry D. Huskey 



Moore School of Electrica,! Engineering 
University of Pennsylvania 



INTRODUCrlON TO RSPORT uN THE 
ELECTRONIC NUIvIERICaL INTEGRATOR AIJD COMPUTOR (ENIAC) 
0. INTRODUCTION 

The Report on the ENIAC consists of five separately bound parts, as 
follows: 

1) ENIAC Operating Manual 

2) ENIAC Maintenance Manual 

3) Part I, Technical Description of the ENI^C 

Voluiae I - Chapters I to VI 

4) Part I, Technical Description of the ENIAC 

Volume II - Chapters VII to XI 

5) Part II, Technical Description of the ENIaC 

Included with the Operating Manual and Parts I and II of the Technical Description 
are all drawings (sec Table 0.3 below) which are required for understanding these 
reports. The Maintenance Manual assumes access to the complete file of ENIAC 
drawings , 

Part I of the Technical Description is intended for those who wish 
to have a general under sta.nding of how the ENIAC works, without concerning them- 
selves with the details of the circuits; it assmnes no knowledge of electronics- 
•r circuit theory. Part II is intended for those who require a detailed under- 
standing of the circuits* Its organization, to a great extent, duplicates that 
of Part I so as to make cross ref-;3rencing between the two parts easy. 

The ENIAC .Operating Manual contains a complete set of instructions 
for operating the ENIAC. It includes very little explanatory material, and 
hence assumes familiarity with Part I of the Technical Description of the ENIAC . 
The ENIAC Maintenance Manual includes description of the various test units and 
procedures for testing, as well as a list of common and probable sources of 
trouble. It assumes a complete understanding of the circuits of the ENInC, i.e., 
a knowledge of both Parts I and II of the Technical Description of the ENIAC . 



The Report on the ENIAC and the complete file of ENIAC drawings 
constitute a complete description and set of instructions for operation and 
maintenance of the machine. The drawings carry a momber of the form PX-n-m, 
The following tables give the classification according to this numbering system. 



TABLE 0.1 


Values of 


Division 




n 






1 


General 




2 


Test Equipment 




3 


Racks and Panels 




4 


Trays, Cables, i.daptors, and Load Boxes 




5 


Accumulators 




6 


High Speed Multiplier 




7 


Function Table 




8 


Master Prograi^imer 




9 


Cycling Unit and Initiating Unit 




10 


Divider and Square Rooter 




11 


Constant Transmitter 




12 


Printer 




13 


Power Supplies 





i /alu.^s of 



TABLE 0.2 



Subject 



1 101-200 


Mring Diagr^ams 


201-300 


Mechanical Drawings 


301-400 


Report Drawings 


401-500 


Illustration Problem Sot-Ups, 



The reader of this report will be primarily interested in the types 
of drawings listed in the following paragraphs, A table on page 4 gives the 
corresponding drawing number for each unit of the ENIAC. 

1) Front Panel Drav/ings. These drawings show in some detail the 
switches, sockets, etc., for each panel of each unit. They contain the 
essential instructions for setting up a problem on the ENIaC, 

2) Front View Drawings, There is one of these drawings for each 
kind of panel used in the various units of the ENIAC, These show the relative 
position of the trays and the location of the various neon lights. Since these 
drawings show the neon lights, they can be used to check the proper operation of 
the various units, 

3) Block Diagrams. These drawings illustrate the logical essentials 
of the internal circuits of each unit. That is, resistors, condensers, and 

' some other electrical details are not shown; but complete channels (paths of 
pulses or gates representing numbers or program signals) are shown in all their 
multiplicity. These drawings will be of interest to those who are interested 
in Parts I and II of the Technical Report, 

4) Cross-section Diagrams, These drawings are electronically complete 
except that only one channel is shown where there is more than one. Thus, these 
drawings show every resistor and condenser and any other electronic elements . 
belonging to any circuit. These drawings will be of particular interest to 

the maintenance personnel and to those reading Part II of the technical report, 

5) Detail Drawings, All other drawings of the ENIAC come under 
this heading, A complete file of drawings is available at the location of the 
ENIAC-^. 



Table 0.3 
ENIAC DRAiflNGS 



Unit 



Initiating 
Unit 



Front Panel 



PX-.9-302 
9~3Q2R 



Front View 



PX-9-305 



Block Diagram 



PX-9-307 



Cross - Section 



Cycling Unit 



PX-9-303 
9~303R 



PX-9->304 



PX-9-307 



Accumulator 



PX-5-301 



PX-5-305 



PX-5-304 
PX-6-3O8 



PX-5-115 



PX-6-112A 
6-112B 



Multiplier 



Function Table 



PX-6-302 
6-302R 
6-303 
6-303R 
6-304 
6-3Q4R 



PX-6-309 



Divider and 
Square Rooter 



PX-7-302 
7-302R 
7-303 

7-303R 



PX-7-305 



PX-7-304 



PX-10-301 
IO-3OIR 



PX-lO-302 
PX-11-306 



PX-IO-304 



PX-7-117 
7-118 



PX-11-116 
11-309 
(C.T. and R.) 



Constant Trans- 
mitter 



Printer 



PX-ll-302 
11-302R 
11-303 
II-3O3R 
11-304 
11-304R 



PX-ll-307 



Master Pro- 
grammer 



PX-12-301 
I2-3OIR 
12-302 
12-302R 
12-303 
12-3Q3R 



PX-I2-3O6 



PX-12-307 



PX-8-301 
8-3OIR 
8-302 
8-302R 



PX-8-303 



PX-8-304 



Other drawings of particular interest: 



PX-12-115 



PX-8-102 



Floor Plan PX-1-302 

A.C. Wiring PX-1-303 

im Reader and PX-11-119 

plugboard PX-11-305 

Interconnection of Multiplier and iiccumulators 
Interconnection of Divider and Accumulators 



IBM Punch and 

Plugboard 

Pulse .amplifier and 

Block Diagram 



PX-12-112 

PX-12-305 

PX-4-.302 

PX-4-301 

PX-6-311 

PX-10^307 



The front vieiv draiwings and the large front panel drawings (whose 
numbers do not end with "R") are bound as a part of the Operator* s Manual, 

Included with the report is a folder containing all the drawings 
listed in the above table except the large front panel (see above) drawings, 

1. GENERAL INSTRUCTIONS FOR OPERi\TING PERSOrWX 

1. Inform maintenance personnel iinmediately of any trouble and note 
same in the log book. 

2. Occasionally check the filament fuse indicator lights (refer to 
front view drawings bound in this volume); if any are out turn off the d-c power 
(switch is located on a-c distribution panel, see PX-1-304). 

3. If ENIAC shuts down from overheating do not try to restart; call 
maintenance personnel. If any panel runs consistently much hotter than the 
others, do the same, 

4. The d-c power should be turned en only with operation switch 
(either on cycling unit or on the hand control) turned to "continuous". After 
the d-c has been on a few seconds it may be turned to cither of the other two 
positions. Failure to follow this rule causes certain d-c fuses to blow, -240 
and -415 in particular, 

5. As a general matter certain units not being used may have their 
heaters turned off. In such cases it is unnecessary to remove the d-c power or 
even to turn off the d-c power when turning on these units. On the other hand the 
three panels of the constant transmitter must be turned on or off simultaneousl2/, 

6. Do not remove any covers, front or back. 

7. Do not open d-c fuse cabinet with the d-c pov/er turned on. This 
noo only exposes a person to voltage differences of around 1500 volts but the 



person may be burned by flying pieces of molten fuse wire in case a fuse should 
blow, 

8, Padlocks are provided for locking the d-c power off» Lock the 
power off and carry the key with you as long as you are working on the machine, 

9a Do not remove accumulator interconnector plugs, or function table 
or IM machine connector cables, while the d-c is on. All other front panel 
plugs may be safely moved while the power is on, 

15, Do not pull directly on wire or cable; always use the plug case 
as a grip, 

11, Do not put sharp bends in cables or hang anything on them, 

12, Do not leave cables dangling on the floor. 

13, Do not pound or force plugs; if they do not respond to steady 
pressure notify maintenance personnel, 

14» Do not leave IBM cable connectors or portable function table 
connectors lying out in the open, keep in the receptacles provided. Also, make 
use of the ramps to protect the cables of any such units which are connected to 
the EMIAC. 

15. Do not force any switches, 

16. Keep the door to the room closed to keep out dust, avoid stirring 
up or producing dust, 

17. Always move the portable function tables with care. Keep the 
brakes on when not moving them, 

2, PRQBLEt/I SET UP RQ^IARKS 

2,1, WM) FOR SYSTBCTIC CHICCKS 

Since the ENIAC makes use of a hierarchy of channels (first, in that a 



n\im.ber of units may be carrying on computations simultaneously; second, in that 
it always handles ten to twenty digits of a number simultaneously} and third, 
in that certain units use a coded system giving four channels for each digit) 
running a standard check problem is not a sufficient check on the accuracy of 
the results. Thus, in arranging a problem for the ENIAC provision should be 
made for occasional systematic checks of all the units. 

Procedures for systematic checking are described in some detail in 
the maintenance manual. Brief procedures will be outlined here for the numerical 
units. The following test procedures are not comprehensive tests and the ex- 
perienced operator vdll perhaps use variations of them. In particular, the 
tests given below are not designed to check the operation of the various program 
controls, Hov/ever, they are designed to check the numerical circuits in each 
unit and to a considerable extent check the program control used to carry out 
the test. 
2.2. JESTING AN ACCUl^UTOR 

Cards should be prepared as follows: 

1. P 11111 11111 

2. P 00000 OOOOl 

The numbers should be so placed on a card that one group in the constant trans- 
mitter, sa.y A , corresponds to these numbers. Next, a master programmer stepper 
should be used to transmit the first number into the accumulators which are to 
be tested eighteen times. At this time the accuimilators should read 

M 99999 99998 
and all stages of each decade have been checked as well as the delayed carry-over 
circuits. Mow th^^ stepper (used above) should cause the reader to read the next 
card and the number to be transmitted to the accumulators twice. This should 



give 



P 00000 00000 
and checks the direct carry-over circuits. Note that this test assumes that 
the significant figure switch is set to "10". If this is not so the operator 
can modify the above procedure to take care of this. 

This test does not chock the following circuits (for a complete check- 
ing procedure see the maintenance manual): 



Transmission circuits 
Clearing circuits 
Repeater ring 



Input channels (except for the one used) 
Prograjn controls (except for the one used) 



2.3. TESTING THE MULTIPLIER 

The following set of cards should be prepared. 
Card Multiplier 



iviuxtipiier 
P 00000 00000 

p 11111 11111 
p 11111 11111 



Multiplicand 

p 11111 mil 
p mil mil 

P 22222 22222 



10 
11 
12 



'? mil mil 

P 22222 22222 
P 22222 22222 



P 99999 99999 

p mil mil 

P 22222 22222 



82 
83 
84 
85 



P 99999 99999 

fP mil mil 

M mil mil 

M mil mil 



P 99999 99999 

M mil mil 
p mil iim 
M mil mil 



On a second set of cards, or on these same cards in different fields 
the proper answers should be punched. Note that these answers will depend upon 
when ten or twenty digit products are used, that is, whether the product 
accumulators are used as ten or twenty digit accumulators. 

There are two methods of using these cards to check the numerical 
circuits of the multiplier. One is to have the answer on the same card and 
arrange for its transmission to the product accumulators with its sign changed 
(or the sign of one of the factors may be changed). In this case the whole 
sequence of cards in run and the presence of "zero" in the product accumulators 
indicates (with high probability since there could be compensating errors) that 
the numerical circuits are all right. 

A second method is to run the test and cause the answers to be punched 
on other cards. These results may then be compared with standard answers by 
use of the reproducing punch. 

This procedure does not check the following: 
Rounding off circuits 
Program controls. (other than the one used), 

2.4. TO TEST h FUNCTION TABLE 

An accumulator is used to build up the argument, A program control 
on the function table has its function switch set to "~2" and a second switch 
has its argument set to "+2". 

The programming is so arranged that the "-2" program is activated and 
the output sent to an accumulator associated with the printer. The result is 
punched on a card, "one" is added to the argument, and the process repeated. 



10 



The master programmer can be used to repeat the "-2" program 96 tiraes and then 
alternately activate the "-2" and the "+2" prograjn four more times, (Or 
various other schemes may be devised to obtain all IO4 entries to the function 
table.) The cards punched in this manner can then be compared with a standard 
deck. 

Note that the above check is not a systematic check of the numerical 
circuits as a whole. In other >vords this check should be repeated if any switches 
on the portable table (or on panel No, 2) are changed. 

Furthermore, the above procedure does not check the various program 
controls of the function table. 

2.5. TO TEST THE DIVIDER AND SQUARE ROOTER 

The divider and square rooter can best be checked by performing test 
division problems and square root problems. Drawing PX-10-111 gives the neons 
which should be lit at various places in the process. The operator can check 
against this by going through the problem at one addition time, 

2.6. CONSTANT TRANSMITTER TEST PROCEDURE 

The 1, 2y 2' , 4 channels in the constant transmitter can all be checked 
simultaneously by reading cards with nine punches on them. Since it is un- 
desirable that the same number be punched in all colujui-s of a card (tliis weakens 
a card increasing the probability of "jamming" in the feeding mechanism of the 
IBM machines) it is suggested that cards be prepared as follows, 

1) 9' s in groups A-rp and B-rr^ 

2) 9' s in groups C^ and D^ 

3) 9's in groups E^^ and F^ 



11 

4) 9's in groups G^^ and H 

LR m 

5) Four more cards similar to above but with minus punches. 

The programniing should be arranged so that the numbers are transmitted 
into acciomulators when they can be inspected Visually or perhaps punched on other 
cards and compared with a standard deck using the reproducing punch. 

Note that Jjj^ and Kjj^ should be checked in a similar manner. (These 
only need be checked for the numbers used in the set-up provided they are re- 
checked any time that some of the switch settings are changed.) 

This procedure does not check all the program controls. 

2.7. PRINTER TEST PROCEDURE 

The printer can be tested by causing all possible digits in each 
channel to be punched and by checking the PM delays. The following cards should 
be prepared. 

1) P 01234 56789 

2) P 11111 11101 

3) P mil 11011 



10) P OUll 11111 

11) P 11111 11111 

The programming should be arranged to cause the numbers on the test 
cards to be read by the IBM reader, transmitted to the printing accumulators, and 
the result punched. The resulting cards may be compared with a standard deck by 
use of the reproducing punch. 

Card number one has the numbers to 9 punched in it to prevent the 
same digit from being punched all across a card. 



12 



If any decades of the master programmor are used in printing they 
may be checked at this time by transmitting the program pulse (used to activate 
the above sequence) into each decade direct input. 

This constitutes a complete test of the printer, 

2.8. TESTING FCR TRANSIENT FAILURES 

If transient failures are suspected a master programmer stepper should 
be used to repeat the appropriate test (such as one of those above) a large 
number of times. 

In case of an accumulator this can be done using only one card (say, 
P 99999 99999) and using a second program control set to aC (receive on a and 
correct) to obtain the one pulse in the units decade. 

For the multiplier it becomes necessary to punch the answers on the 
cards with the factors (see 2.3) and cause these to be transmitted to the 
product accumulators for each multiplication. If more than ten digit answers 
are used the adjusted answer to card 83 must be carefully prepared in order to 
get minus the answer from the constant transmitter to the product accumulators 
(since the constant transmitter only complements at most ten digits at, a time). 

Repetition of a function table test is straight forward. It may be 
worth while to receive into a twenty digit accumulator and repeat the transmission 
10 times, say, and see if the proper number is obtained. 

The square root of zero is perhaps the easiest test to repeat on the 
divider-square rooter. 

The constant transmitter can be caused to transmit any group repeatedly 
to some accumulator. Dust particles may cause transient relay failures, so avoid 
stirring up dust in the ENIAC room. Also, if any relay case is removed, always 



13 



replace in exactly the same position in order not to disturb dust inside the 
case, % 

Transient failures in the printer are probably relay failures^ See 
maintenance manual for list of probable failures. 



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R(NG, 


Placc 

R INC, 


RcCC IV€R. 


• 2 


N-N+': 


DrNff 

6 T 8 9 




3 4 5 


to 


II 


a 

3 
4 


B 

1 
A 


9 
S 
9 
9 


Df,-fi 


OK On 


ON 


OH 


: " \ IonI 

" OK 




ON !on| 




OH <»• 


" ON 


iOM 


2 -A. 
^ 


fl 
R 


i 

Cycucs 


05 OR Dp 

-A0R.+1. 


" 


ON Ion 




|« ♦♦ 


L 


' Ion 


•• 




: 

i 


ON 
ON 


ON 


^^ 


^ 




Ctcus! 


m-1 

3 


1 
2 


l« 


-1 OR-fl, 


*• 


C3) ' 


ONJ 






' '' 1 i 






«l 


Cvcus 


■""■; 1 "i ' 


«t 


Df^oi^D^^ 


1 ^ 


M 


(D n ^ 


R 






4 


DrO(^ Ds 




•• 


" 1 ^ H 


an! 






5 


3 


• 1 DqOR Ds 1 


» 


,^ " ^ io"! : 1 


G 


4 


*• [ DWORDs 




H 


•• 


1 ; ION 






7 


5 


i: 


M «• 


i i !^" 






B 


7 


n 1 I 
1 i 


«• »i 


! i '■" 

1 i 




9 




1 










1 t^jr ; 








IT- 1 


7 
7 


11 
l< 


1 


s 11 

%i 


:®j® 


: W\ 


t .. -(I)' .. 1.. . r t^ 


C€|V€P. 

OFF 

J 


A 


3 


3.4, OR. 

NeiTHtR. 


ON' ON OH ON 




McoN Lamps - 
.Divide Flip -Flop 
P.DeNOMWA TOR Flip- Flop 

3NuM€RftT0R RlNQ — 
4NuM€RflT0R.RlNQ4- 

5.Cl6r\^ Flii^-Flop 

UnT^RLOCK CotNCID€NC€ 

Flip- Flop 
7. 1 NT€^ LOCK Flip- Flop 
aDiJ^tceivi£R 
9.NyE£ceiY€R 
I.O.PRo^f2flMRwciFL IP-Flo^ 
H.PuLstSooRcc R. IP-Flop 

ftNSWCR-DlSPOSRL (h4) 
EcccivcR. NeoKS 

R€C€IV€R. N€ONS 

PLnc€ RinqNcons 
/NoMBcRfoTo C«hr€5PondTo 

D€CfiO€sOFfiNPccu^^ULftT«j 



00 OD 00 0000 00 ©000 



O O O G 
% * 1 4 



O C O C Ot 

» <• ▼ • o* 




-TRnN5cctv€RhA€aMs(h8) 



'Peo<5RAn Ring KJeoNS 



Divider. -Square Rooter 
Promt View 

PX-I0-3QZ 



Foot Notcs - 

©On If Pecvious Pr®c,ram Was R Division. I 

1^ ■ On If DcNoniNftTOR. Is Post rive Wh^n ^gceivcp \n DeNcniNRTOR. QccunuLnToe.. 

(5)-1f, Bcforc DcNOMiNRTOR. \bRDD€D To Or Subteac Tto Fftof^ NuncRftTot^^ Thc NuM€i?ftTr9L h PosiTwc, NeoN^4 Is On ; 

OTH€Rwise N€on'*3 Is On. 
r4)Go€s On Wh€n Interlock Puist is Rcceivco. 
(5)-Go On ONt PlDDiTioN TiM£ Aftcr. IE- 9 
(?) • Cio€5 On : a- In NI Crsc, Two Pddition Tines Pftci^ HL- 9. 

b- In I Cnsc^ In Whichcvcr. Occur.s LftTeR.: Two Rddition Timcs Aftcr 11-3 0(^ ONcfioDiTioNTiMc Qftcr Ncon7 
*^ Only If Mo Overdraft ResuLTb. • 

^ 3^i^l0-(p VVh€R€ ^ IsTHcScTTiNa OrTMr Plpccs Switch. 



^ 




#. # 



■fTCMS. j 



'T 



It !2 W !5" i€ i7 \e V3 ?0 






:~D 



u:,:'^^:r^.*L;^^l£j-f_ > ^i " 



■ 1 






! 1 






r::.] fe f^ L: 



1^dl^j ^jf^'<..^^fL ^^JL^JL 






„- . ^^ 



-o c o o o : o o o o 

21 «£ ?3 ^4 ?5 ?t c'? es ;9 30 



NePTEIR FUiC niECi : 



-i r 



HrRTER f'^j^e kEoTjs 



i 


,...-1....... 

t 


r 







as 



4> 



■9^ 




I rr — " 


~ • 


^_ , 




i i ^ i 


l-l 


^1 


i >" i 


J i ^ 


j -; -r 


ri™- - 


„. 




i ^:^ 


: A i 


1 ^ \ 


>* ; 







•i k„ .; i 

;" >l'^ h'"^ P 1 


i 







iiflrr^ r j..? K: ^ 



! • : 




Mfjn^t Sl^. 



' £:/': i:,oi e^jgi'-js^^hn^ 



,'•. -*•- ^, H ^S ,'^, ■"• '"• A ," 



58^ 





3888888883 

OQOOOOOOO 
.. ,. ,-. - - o Q - - 

P U 

0tf'"^ 



"Drcf^pE Nc:oh 



I'iiJ 


'^,J 


^ 3 


.d:^i^Bf. 


]00QWH 


s 




~: K r ii' ■■■«■ '" ; 

i!A :^>r v^ 1^ 1 ^ 


1 . , 1 


nnf 


— i| — \['~^ 


I'-jLrikJ'-i^] 


•Tli 


^u-lR^P^ ^ Hk 


h 


J ivj I 


' ■ !r ■; U -- i 


Czr 


— - -- - 


..... ..J 



o ^-^ 



BE H H 

030^3000 



i>^!i>|^i.*-|j>'if71 



HZBBBEBaCTP 



00El32IZl0LdEk 



0-! 


7|.!33i3R33 


1 ^ 1 

1 


H ' !" "I 1^ 1 

^ ^___ ^ 1 


r 





ii' G C S> © '^ 

;s © © €^ © (?) a i^ © © 

©©© ©©0 00 0O0 ©0© 



-SrE^'PtR Neons 



"ront Panel 




OTEPPcR Inplt Nfgn^ 



I 



<^/r r/e^y 



^- 



"h- :'6^/;7 Ti^/^y 



ooocoooococ^ 



DOC 



COOOOOOOCOC' 



/-s /-\,— ', -^ '-\r>, 0-'^y^('^0 






\ '~/?/^yir 



Te^y 













» I ' » — u 



>-J voltage hum o£i« 



1^3 yottag** ?9lp-;t-T ewltchaa 

'.Vhlt<» nviab<»rs on the voltage chart in fiesta 
volta.?«f Pt rh«» ends <:>t a pDw>,>r suj^^^ly* Blaei: 
numb«r8 indtoate voltnge pairs U \vMch at i^ust- 
otje ToltBi^o is dsrivej fr-)m a b.leedsir tsip. 

Behind the voltag«> chart are rha oscillo- 
scope Brt ju3tnM»nts, 

The d-c voltnge Qnpll*i>14 ana "-he e-c h'un 
amplitude nf ewry voltng? of the Mil/.C 'say bo 
KOBSUTvi wit: TT.-.;r.v* »^ pQjgt, other volte*2e at 
thlF p«nel. 



Start and stop switcher 

I^jFhiEg the Ft«rt .switch turns th» ambar 
light on and atsrts the Initiating sequecce 
for the ENIAG, turning on th« d-c po»»er supplie? 
the hearers of the various panels, and the ffine, 
and operating the initial clear. V^ier this 
aequenre has been ccmpleted, showin^; that th'> 
ENIAO iF ready to operate, the green lidit yo-ss 
on, 

pushing the stop switch turns the STjIaC 
off, including the hoatej^, the d-c power sup- 
pi i^", srA ^he faii<^. 




THE [NIAC 

ElECTHONIchKxiWCAL InTESRATOR ANftCoMFUTOR 

I>E^(t^•MO^ I>ltk«NIO AND C«NSTA«KTIB 

M«OR[ SCHOOL •vClECTRICAL lN6lNEtR\MG 
OW THB 




D-J power supplies 



Thi? Phows th'* T.iirber of hours the d-<. pow«r 
supply filaments have. been on. 



<'lanr 



sfitch^ 



Though the SI^IAJ 1? initially cleared when- 
ever thrt start switch is operated, an initial 
clear switch is proyidel so that the operator 
can clear the machine with-^'Jt turning 5t o^f. 

The operation selector switch on the cycling 
unit must ba sat at Cent, for initial clearing 
to take place. 
Elective cleer pivjsra ni controls 

Cj - program pulse input teminel for oeltjotive 

cl^er program control, 

Co - program pulse output terra! r el for sel'*,''+iw 

clear program control* 

Trhenever e progren pulse is supplied to a 
C-i, all accumulators set to SC will be •'"or'-xl, 
and e prograii pulse will be emitted frofr. tlie 
corresponding C^ one addition time later. ?or 
neon bulbs of associated transceivers "ei^ 



OC VOLTAGES 





i ! 2 1 a I 4 I J t 6 i r i » : VT >«n^ 



-+LI 



o 



o 



o 



"a 



INITIAL CLE»e 



O 



o o 

READER 



O O 

PRINTER 



IN/MT OUTWJT 

o oj 



o o 

INITIATING PULSE. 



OUTPUT 

10 O 



W©. HH °®o°a °@„ 

'DM °©o°a H°©o °®M °®M H 



^\ - pulse ir.,>ut ter"lnel for printer 

_I(j - program nulse output tergnlnal for prl'ito: 

'..'heT.'vei- « pui-" ia r« -flv-i on ■, 
A pul^e iE amilted from p,^ b" h'k-^ bc \h 
be Ptiiruletsd, hut tin's I'jlll p'-"* ceu;n fi 



'.::]. <^tart« to operate and th^ printer raisy? start to pick up, 
1-" 3*=t up, AJiy tiafs after this pulse is enitted p^ n«iy dQ^in 
^:^':\nff .mtll the first is finished. 



Door Swltoh Shunt 

ordinarily th« ENIAU will 



loi operHte with "ny of ih'i door-^ off, Thie It ■ 



ety feature, otnoe removinpj tbe doorw expo^ea daniiy'rouw voltaigee . If It la 
etiuery to operate the liiNlAi With th»' ^onra' off, this m&y \j« ''.ona by holding 



thin switch clnjed. 



- k-C volta'se mater 

_ A-C voitHeje aelector switch 

Sy moan'!' or thlf awitoh and meter the three phaaes of u.e of th^ two bun 

riynens supplying 110 volts a-c to the filament tfenaforinaru of the various unit» 

nifly b« fwaaured. 



R,^ - puipe Innut terminal fQ:f reader Interlock 
TVj - puli'»e input terminal for reader 
"Rjj - pro<;raro pulse output t erminal for reader 

- ' I ' flgflB Tflminftift fifi ' »fl to do w Uh the' operation of the Ifai 'lard reader, Whan- 

ever h pulse is suppliea to R^ the 1BI<' roader stertw to put a new card in position. 
After the card is read end the relays have set up the donPtant transmitter gates 
the infonnation is ready to be taken from the constant transmitter, A pulee is 
en'itted from Rq after the constant transmitter is ready and after a pulse hea been 
received on Rj^, The operation of the constant transmitter program controls is 
described on iP;t-ll-302, 

!leader start switch 

Hf, - Tonainal for parallelinfi: the reader start switch 
Operation of the reader start switch star*.-" THM 
has been read a pulee is emitted from Rq. 

i>q is a tominal for paralleling the resder start switch with a switch which 
may be carried anywhere »iround the n^'lAC and which is connected to thifi terminal 
vie e pro^rain line which has no load bo^ or by means of a apacial cablq. 



reader. After the card 



-Inltlet inf^ pulse switch 

I„ - Terminal for paTaTleling the initi ating nui^se switch 

To - Frotjraa uulse output terminal for ir^ll^ie tlr y!; pu1 , !;9 

"" "/henever the initiating pulse switch is pushed n single program pulse (i.e., 

c ffated GPP) is er^ltted from I^, This pulsa may be ured to initiate any sequence 
of oporetlons set up on the ENIAC. 

Is Is a terminal for paralleling the initiatlna pulse switch with a switch 
which TrtHy be carrted anywhore around the KMIAC and which is connected to this term- 
inal via a iir.ograra line which has no load box , or by means of a special 
cable.. 



Note: ro^'tab le Control Station is shown on PX-9*303. 



WOORE SCHOOL Of ELECTRICAL ENCIN££RINC 

UNIVERSITY OF PENNSYLVANIA 




INITIATINQ UNIT raHrFMK— 






Aoorov«a Oy : 



YM-mt 




CM 

lopJULIULfULILfULIL 
.f-IUUUUULIULIL. 

ip-Jl 

»!» fUI 



JUL 



A.m 


n nn n 






I<P 


n 






ceo. 


r 


n 


— \^ 


np 




n 



OO l234&e7««IOUI2l3l4IAItl7iB»20Q 



HEATWS 
OTFQ ON 






o 



irULS^lMMTM 



^^Z^J^P 1 


"^^G 


^ if 


>w^ 


^ CC5 


CP^^ 


HP 


(Kt: 


sc<; 





««H.St' COHT. 



^. 



H 



H^ 



' nhown c 



Oscllloacope on which oan bo mw. thrt oyaHn« unit pulsoo axid gnt.Pa, th« a«l«»'^tiv« ol^ar ««t« (iiUQj (rhen U la prograraMd), 
or any »xt*»rn(a '^l;p:al traJirtclttM to the twrmlnta rn8rk-i<! "Lxt,", The <vllng wU p-ils***! and (jotas to be 3"ien ar« show 
on tho GCoonjiMiylnu cthort, bohlnd whl<'h aro the occjilloflcope ndju8tra«nt«,. The oscinosf^op* Input (swUoh salecto thP algnal 
thfl 08<?in,onoop«, A flgnal rany b» trHrismltt9<l to th« temiiual "Srt." on « proRrom lln* which hap no lr.i,d 



Oroan Pilot Light 

Same as on Initiating Unit 

front Panel 



Qporatlon Salactor Switch 
TtA oontrol by thla BwltoU 
and the 1 pulso • 1 add. 
push button la thi) satai rs 
that provldHfi by the switch 
on the oyollng unit front 
panal. Note: The switch 
which is not being uaed 
must be set to "1 pulse**. 



1 Pulse - 1 Add -Push Button" 



. Hertar switch 



e OPERATION e 


o 


1 PULU 


C^ RCADIR f^ c 
® iTART \^ © 


©v".':;j^ O® 


©i:r O® 


e ENIAC e 






Push Buttons 

Control provided Is the saaa 
as provided by corrosoonding 
push buttons on Initiating 
Unit Fmnt Pec el - See PX-9- 302, 



Portable Control Station 



* Fu3h button for 1 oulsg limy :>r ong addition t line 

PA- Terminal for paralleling thin' yii?-h button 

Operation sel^ator awitch 

lA and gont. -» T^rmlaalf; for parwllt'llng the oporwtlon seloetor pwitch 

—Tho cycling unit hns thrse modes of operation, ."elected by the switch nr its associated terminals (lA Coct )• 

1) Oont, - Tho pulses and rpX<^.T, are given out cont^nucusly, ' "^ * 

2) 1 Add, - The pulses tiud ^^tes for one addition M.-ne are etnitled wtianever the push-button for 1 pulse tlm? or 1 

addition tine le pushed, 

3) 1 pulse - The pulses wid i?«tes for one pulse time ere erai^tcid whenever the push-button for 1 pulee time or 1 

addition tliro is purhed, 
—portable pnfih hut tone may b« u?ed in connection with terminals pA, lA, and Coiit. These may be plugged Into 

a p-og.rar3 lin.'? wJiich has no load box and that line plugged into the terminalB. 
IJ A push button oonnpnted to PA parall-^1? the 1 pulse and 1 Add. push button. 
2) Pu-'-h buttons cor.n^.cted t- lA and Cont. enable thf; operator to parsllel the operation aalector switch. '.Vhen this 

awitoli 1"- .Tet '•-• the 1 Pulse position, holding closed the button connected to lA gives th« 1 addition time 

mode of opf^ratlon, while holding closed tne button connected to Cont. gives continuous operation. 



MOORE SCHOQL' OF ELECTRICAL tNGINEERIMO 
UNIVERSITY OF PENMSYL¥ANIA 



CyCUNG UNIT fPONT PML 



Drawn t>> 

DtUI>44 






AopfOw<n ov : 



PX-9-3()3 



Switches 1-4: O peration 
swltchaa for non-repeat 
program pontrolB. 



Clear correct 8wltch~ 



Switches ^1?: o peration — 
switches for repeat 
program controle. 



Itie digit teminale are to be connected to the digit trunks (trays) (see PX-5-305} by the digit (tables for 
rec^iTing and transmitting numbare. The operation of these teiroinala is govoruod-by the program controls of the 
accumulator. (Thus digit pulses transraittod on a trunk to which the oC tenninal is connected are recelvod only if 
the accumulator is programoed to raoeive on oi }. 

Multiplication by powers of tan may be a-aofap.liPh'i by means of shiftera (PX-^lO'l) which trar>sposa the 
digit wires, shiftera ciust b« p laced orO^ in -31^1 1 input teminala, not in digit outpu t teminals . 

Deleters (PX-^-Td9) are used in conne::tion witlTthe' significant Tfgureo switch; they may be placed only 
in digit output teminals. 



Digit Input Tun/iinals 






Digit output Torrainals 






2 ^.•J 



5 c<c5 



■^a^ 



OFF Q ON 







2 c<0 3 c<0 4 c<0 



1 fO 

»*.« 



Ml 



9 c<0 



10 CO 



ScO 

o 

6 54 



s^P 

i(^> 






SUi 



12 c<0 



4 » e 



+ 56 



4 5 t, 



♦'> 



{^) II im W \9t\ II la^> I I \m "M\ II \gb\ II m 

©^H V@o V©o U°@o °®on '@o°©o HH °@oH 



(SS 



aQQQDDD 



QS 



aaanaaa 



a-®-c 



pQoaaDQ 



a 



10 decade accumulator 



1^0 decade accumulator 



V: Ace, interconnector cuble (vertical.) (FX-5-l?l) 

H: Aco, interconnector cable (horizontal) (PX^-110) 

A indioaten popltlon of aco. interconnector terminal Joed box (PX-5-109) 

Kote: Each of the 2li program controls of the 20 decade accumulator 
governs the operation of all decades and of the common pro- 
graintDing circuitp of both accumulators. 



Terminals li. 21, 



Program pulse input terminals for non-rep 
program controls 1-U respectively. 

Terminals" ^i. 121 

program pulse input terminals for repeat 
program controls 5-12 respectively. 



Non-repeat pro gram controls 1-4 . 



Terminals 5o . 6o 12o 

Frogram pulsa output teminals : 
repeat- program controls 5-12 
respect Ivoiy, 



1) Program pulse input terminal (whan stimulated with prosmn puleo causes program control to program operation 
in accordance with its switch settings) 

2) Operation switch 

3) Clearwaorreot switch 

\\ Associated receiver (for neon bulbs sea PX-5-305) 

Re peat program controls 5^12. 

These operate for n additions times, where n is the setting of the repeat switch. 
Each control consists of • 

i; Program pulse input tarmlDfll (when stlrmjlated with prrjgrara pulse causes program control to program operation 
In accordance with its switch settings), 

2} Program pulse output terminal (emits program pulse at end of nth addition time} 

3) operation switch 

4) Cleair-correct switch 

5) Repeat switch 

6) Associated transceiver (For neon bulbs see PX-5-305) 



If thlf switch la set to 3C the accumulator is clsared whenevor s program pulse is transmitted 
I on« of the selective clear Inputs of the initiating unit. 



. 3iCTif leant fl.- nires ttfltch 

This switch determines which decade (if any) is cleared to 5 instead of whenever the accumu- 
iBtoK IP cleared and en which line the subtract pulse is transmitted on a subtract transmission 
It does not govern the del-tion of nnn-signif leant dlgitr,; this must be done by means of rteleters 
(PX-1W109J (When the switch If set to ru, deleter n-jn-bor rasho'ild be used, etc,) 

If the switch is set to m, decade lo-m (counting from the right) Is cleared to 5, and the 
subtract pulse Is transmitted on digit line 11-^, 

When a 20 deeadn accumulator is formed, the two significant figure switches are to be uped as 

(A) mien 9 or less significant figures are desired, the left hand switch is set to the number 
desired and the right hand switch to 10. 

(B) When 10 or more significant figures ar^ desired, the left hand switch is sat to 10 and the 
right hand switch set so that the sun of the two switch readings equals the number of significant 
figures desired. 

repaat proRrou controls 5-12 

■^ach switch governs the number of addition times its repeat program control operates. 



O peration switches and claar - eorrect switches ; 

TSiasa operate together in the foUowln^s manner: 



Operation switch 
setting 


Operation prograimad 
by operation switch 


Operation programmed by 
clear-correct switch if 
86^ to c. 


oC 
Y 
£ 


Heceive on oL digit input terminal 
Receive or fi digit input tenninal 
lieoeive on f digit input terminal 
l-tecelva on S digit input terminal 
Receive on £ digit input terminal 


A correct pulse (in inter- 
nally gated 1' pulse) is 
placed in the Juiits decade 
at each addition time. 




A 

AS 

S 


N«thine 

Trensinit on idd digit output terminal 
Transmit on both add and subtract nl,p;it 

output terminal 
Transmit on subtract digit output terminal 


The accumulator is cleared 
at the end of the last add- 
ition time of the program. 



MOORC SCHOOL Of ELECTtlCAl CMOINCCIIINC 
UMIVERSITY OF PENNSVIVAMIA 



ACCUMULATOQ fK)NT PANtL 



Orwmr\ by; 

i).EOCLSACK 

DEC 1944 



CnmcMmd by 



PX-5^01 



Multlpllar Ace. 
Clear Switch 



Multiplicand Ace, 
Clear 3witoh 



Ilumber of the pro«*ain 
control to irtilch the switches 
In a given column belong and 
to which the corresoonding 
numbered program input and 
program output terminals be- 
long. 




'@:@:@M °©>o HH °@M %n m m 



erminals 11. gj.. 



..gHi 



Program pulse Input tannlnela for program controls 
1-24 respectively. 

Terminals lo„ 2o , 2^0 

Program pulse output terminals for program controls 
1-21^ respectively. 



There ara 2k multiplier program controls, each consisting of 



Taminale R»t - u< 

Program pulse output terminals associated respect- 
ively with A.9.Y. J.C r.D the 24 multiplier' 
accuriulator function switches, 

Temlnele DH - pt 

Program pulne outout terminals aBsociated ronpec- 
tlvely with *. 9 . r, «..c on the pl' multiplicand 
accumulator function switches. 



10 



1) Program pulse input temlnal fwhen stimulated with nm^rar. pulBo causes program control to 

program multiplication in accordance with its switch Rettin^'sJ. 
S) program pulse output te-irinal (emits pro.'ram pulss on complntior. of multiple cat ion). 
3) Multiplier ace. recel-- -~<*"W •^ i- /. 

l^) Multlpl 

5) llultipl 

6) l;lultlpl 

7) Significant figures switch' 
i) riacoe switch 
9) Product dlBpoBBl switch 

Associated transceiver- 



pller ace. receive switch "1 

pilar Bcc. clear switch [ 

plicand ace. receive switch ( Descrl 

pllcand ace. ol«ar switch J 

■■ > 



—Described on P'A-(>-^03 
—Described on ?a-6-304 
-For neon bulbs see i'a-6-309 



The high-speed multiplier operates in conjunction with four or six associated accumulators. These ar» the 
multiplier aco. (^^9), the multiplicand ace. (#10). the left-hand partial products ace. (#11 anroer^ 
haps #12) and the right-hand products ace, f#13 and perhaps #l4). ?or a diagram showing the Intei- 
'connections, of the higb-epeed multiplier with Us associated accumulators see PX-6-3H, 



ItipUer ace, by n^ans of the static cable running into 
If this svritch is set on C, the multiplier is cleared 



^iUlt1plier Acciunulator Clear Switch 
This governs the clearing of the 
the multiplier ace, Vt/i plug-in unit. 
during the last addition time of the raultlplicatii 

Multiplier Accuffiulator '{ecelve Switch 

tt-henever a pro^rnm pul5e is received on a program input teanlnal of a given program control 
a pulse is inihediately emitted from HO^- R£ , or not at all, accordingly bc the multiplier ecc 
function switch of that program control is set on OC -^ , or o respectively. These pulses may* 
jL^^^r T'^ the multiplier ace, to receive the multiplior during the next addition time by 
having them ransmitted to properly set multiplier ace. program controls, i.e. by connectl^ 
dit'llgio five program pulse inputs of the multiplier ace. (#9) and setting the corresponding 
operctlon swltchea to receive on cC - ^ respectively. 

It is to be noted that all 2k multiplier program controls cause pulses to be emitted on ^ ~n^ 
so that only five multiplier ace, program controls are required to receive all 24 multipliers. 



i.:ultlpllcand Acciunulator jlear Switch 



cl«« Jn^' jperates the a«me as the multiplier ace. clear switch except that it governs the 
clearing of the multiplicand ace. 



i.rultlplleand Accumulator Receive Switch 



rhi« -,u..--tions the same «s the m-altlplier ace, receive switch except that It gives out 
program ..:<pu m terminals DoCto D£ and may be used with the multiplicand ace, (#10). 



Multiplier rlaces Switch 



Product Disposal swl*-.' 



MOORC SCHOOL OF ELECTHICAl CN^INCCRINC 
UNIVERSITY Of PENMSVLVANU 



HIGH-SPECP MULTIPLIER FRONT PANEL NO.i 



J.EOEISKK 

DEC (941 






PX-6-302 




Slgttlficant Figures switch 

This switch mpy be used to give a variable round-off; I.e., a product lAich is rounded off in a 
different place for each program control. This switch governs the addition of 5 pulses Into the 
proper placrt of the left-hand product ace, (#11, 12) during the second addition time of the multi- 
plication. 

It does not control the deletion of the non-signif leant digits of the product nor the placing 
of the subtract pulse in the proper channel of the product on a subtract transmission. Since these 
vary with the setting of the significant figures switch, they must be taken xiare of at the accumulator 
which receivoB the product. Hence in cases where every piT>duct is to be rounded-off to the same 
nvmber of places, It. la best to use the round-off facilities of the right-hand product ace, (#13, 1^), 



Places Switch 

This governs the number of places of the multiplier that are to be used In the multiplication. 
The multiplier digits are used from left to right, sp that the most si^piif leant digits are used first. 
The places referred to are the pieces of the multiplier ace, counted from the left. 

The places switch ia completely independent of the significant figures switch. The reason for 
this is that all olglts of the multiplicand are used in the multiplication process. The only purpose 
of the places switch ia to savp *lia«. 



Time schediile for multiplication 

A multiplication requires from 6 to !•* addition tiaao (depending upon the setting of the 
places switch) including the tl.tne required for receiving the multiplier and multiplicand, but 
not iqcliidlng the time required for disposal of the product. 

Addition time Operation 

(Program input pulse received at end of 0th 
addition time) 

1 Multiplier and multiplicand received 

2 Five roiuid-off pulses transmitted to left-hand product ace, (#11, 12) 

3 Multiplicand mrOtiplied by first place (10th decade) of multiplier 
and loft and right hand components transmitted to left and right hand 
product aco* 

This is continued up to the p+2d addition time, where p setting of 
places switch 

Complocent corrections are made when necessary. 

Accumulated left hand products are added into accumulated right hand 
products, 

(program output pulse and answer disposal pulsesenixted at end of p+Uth addition time) 



P + 2 



P+3 
P+U 



MOORe SCHOOL OF ELECTKICAl CMCINCEIIINC 
UMIVERSITY Of PCNNSVLVAMIA 



HIGH-SPEEP hULTlPLIEB FROKIT PANEL Na2 



Orawft by: 
DEC. 1944 



r/^'/', /r-Zfi^lif 



FX-6-S03 



Important note con^eruintf the pwrtJHl p-^oaucts digit oxitput t« rtalnala 

These teralnnls are to bo aemi-pemanently coimaated to- the OL digit Input tannlnals (see note on teminaln l,r) 
of the product aocumulatopf (^^11, 12, 13, 1^) by trays or cables not uged for any; ^ " . '': , fiQ^ ti"^P°y .' 11° load boxaa ara t o 
be used. The digit pulses omitted from these temlnals era not supplied from transmitters, hvt from Invarter tubas whi'ch 
eannct ^a oonaaotad in parallel with anything else and vriiich have their mm resistors. Hanoa the 4 digit input terminals 
of tiio product aceumulatorp cannot be uaad for reoaiving any other iiunbera. 

Ho shiftars or delaters era to ba used. Accumulators 11 and 1? end acovunulators 13 and Xh are pair<»d whan more 
than eight plases Is dealrad In the product, 

Th« load on these outputs must be kept as anall as possible. RacoEmoadac) nathnd -if nonnection ia; 



By special "able to Jiccumulator 11. 

By short cable to trhy (only one tray), and short cablo to Accumulator 1?. 
By special cablo to Accumulator 13. 
R.H. # 2 Similar to I .H. #2 and Aoeunulator 12, 

Digit output Tenainals for partial rroducta - 



L.K. n 

L.ll. il'2 
K.H. # 1 



See also drawing PX-6-3H 



LctrHAN* 
fVtKTiML Pwtucn 
Rcc.i C»11) 



Lett H«nd 
p«»t»l prooocts 



HULTmiRALCWlXArCK 



n'jr!i".5tt/icniMw.iiT«)» 



P 



U^ 




1 5 6 7 



f10l.TlPlIl/«D>WlAfW 



:o 



mjiBJi/<qmjii» 



rp 



mj^»mi-\inMm 



:p 



m-rnxmoumum 



19; 



m 



4 /r>»^ 



WHMtttKiaWltlTOK 



mQi 



^"Jj'.O 



n 



NUCnnXM'MDNH.RrK 






wm^Zj- 



HOOM 

O |— , o 

HI6M Sr^D 
PANELS 



MUrURMBMUUm 



!a 






21 7' 



wfrrr 



Product 
flccj (♦t3> 



Kiqht Hand 

Pkoouct 

ftccg(l4) 



!o| 



MitniCM/nwMiiTfM 



8 

vammrtwB 



m;-. 



>rM\0 



rmmruflt Mcuwuwi 



5q 



WTfMMMtunAKriK 



23^ * 5 , 

8 / 



TO^ 



JMltUtt/ftlWiUffOK' 






^ 



:0 



IMTIflKdM ftOMfl-liat 



247^ 



siGmcMrncMn 



lojr 



«t 






'««l^c 



ISRci 



/<So*:.^ 



W©M^Q)M 



©o©o ©o®o ©o©o°^°©o°©o°H HH HH H^ 



Terminals A -ASC 

Program output terminals associated 
respectively with A, S, AS, AC, SC, 
ASC, on product disposal switch. 



Termlnala T^, DS, ? 

program pulso outout terminels for trananittlng pulses used in the 
prograraaing of each multiplication: 

DS - A program pulse la emitted at the end of the p-f 2d addition time 
if the mviltlpliar is negative. Soml-nermanent connections must be 
established so that this pulso prograiis the multiplicand ace. to trans- 
mit subtract and the right hand product accumulator I (#13) ^-o receive. 

1^ - A program pulse is enitted at the end of the p+2d addition tine 
if the multiplicand is negative. Semi-permanent connections must be 
eatablishad so that this pulse programs the multiplier ace. (ii*9) to 
transmit subtract and the left hand partial products ace. I (#11) to 
receive, 

F - A program pulse la emitted at the end of the p+3d addition time, 
Poml-permanent connections must be established so that this pulse pro- 
grams the left liand partial products accumulator (i^ll, 12) to transmit 
add (without shifting) and clear and programs the right hand product 
accumulator (<'13, 1**) to receive, or vice-vorsa. 

Ta ml gals 2.ȣ, 

Receiver cathode follower buffer output lines. These er^ to be uaad to 
program the product ace, to r<doeivo the partial products. The following 
eeml—permQnent counectlona ere to be establiPhod, 

1»- \ is to be connected via ace. intarconnactor cable (;jjult.j 
(p:£-.^-131) Into tha Intarconnector termlnala Irj^ and i^o of 
left-hand partial products ace, 1 (#11), The 8 digit Input 
terminal is to be used to receive the partial products. 
2, r Ifl to be similarly connected Into riglit-hand product accumu- 
lator I (j^'lS). Likftwiae, the e»c digit input terminal is to be 
used to receive the partial products. 



Product disposal switch 



This switch operates In conjunction with program pulse output terminals A through ASC and 
provides program facilities for the disposal of all 2U products using at most 6 program controls 
of the right-hand product accumulator (#13, I'^J. 

At the end of the p+l+th addition time (l.a., at the sai 
Is emitted) a program pulse is emitted from A-ASC according t( 
switch of the program control being used, 

Saml -permanent connections may be establiahed by connecting A through ASC to six program 
pulse inputs of the right-hand product ace, (#13, l'^) and setting the corresponding operation 
switches and clear-correct switches to transmit on A-ASC. The program control output pulse may 
be used to stimulate that unit of the EiaAC which is to receive the transmitted product. 



e time as th*" program output -pulse 
the setting of the product disposal 



MOORC SCHOOL OF ELECTKKAi CIICINCCIIINC 
UMIVERSITY OF PCNNSVIVAMU 



HIGH-SPEED MULTIPLIER FRONT PAMEL NO. 3 



J.ttELSKK 



CnttTttttO oy; 



PX-6-304 



These Trays To be UsED OnuTo 
CftRRY The pRRTiflL Products 
f^ND Fof< No Other Purpose 



No Load Boxes Af^fToBe 
Used On The5e Line5 



NDDDaDDDs 



^-Q 



a. p -)• fc 



O O Q O O 



r-flDDDDDDDB 



L^] 



O O O 



H I CH 



PflNEU^I 



5 PEE D M ULTI P 

PflNEL*2 




I ER 



PRNEL^J 



I FTT H^ND PQR-TlflL PRODUC r fled 



qDddddddd 

LE FT H OND PflRTlflL PRoDUCTRCcH 

IfPODiqit Proooctj 
Are Found. '-' 



See PX-5-l3l-g 



r^DD DDDDDd 

WfiHT HOHP PflRTIflL < riWfll PBOPUC Tflcc: 



AS 



(3 |(^ |fl Is 



DUD DDDDno 

awHSNOlflRTIflL 9 FlrtflLPROOWCT Acc.lT 



flee. If 20 DiciTPftoDuc 
w Are fouNP. 



T] 



Note- Horizontal Lines Abowe The Units Rei>i^E5ENT Diqit Trrys. 
The DcTTtD Lines RepRESEMT TRftYs Which Need Be Used 
Only When 20 Diqit Products Are Found, 



MOORE SCHOOL°^ELECTR|CRL ENQINEERINQ 
UNIVERSITY ^^PENNSLVANIP 



Interconneqtiow Of Hich-5peed MultiplifrWith 

fisSOCIflTED flcCUMULRTORS'^ PX-6"3|| 



Arjjarwnt; In put tamlnal 

ThiK! Input is op«n for w-'flptlon of the tw'>-dlgit arg<unant dvir.hig th«» 2nd ndditton 
tlm» of opwratJon, Thfl units plac^« Ih r«i;*lv«d on .1 ln<i I, tho t^na place on tim |, 
Shlftcra (PX-U-lo*t) should ba usad iu tlils tonninal to f>hlf1 thn src'irnont It' It "won 
fruc.i othor decadop than tlio 'jtb and 6t\x» T>'.o othar llu«8 of this t.or'Ainal «r« uncon- 
ntjoted, ;^o a d«.l(»ter 1« not requlr«d« „ 

Tlio acoiculator w»Uch tran.-w^.ts tho Br(jun«nt nay b<i pijjocrnrjit'd frow terrrtlnalft IJC 



and G. 



Th« function v„ol*< autorntljally clearp U." BrKi-imont at tha end of each op«n 



f. i on t 




HH H@o ©oH ^oH ^o^c HH 



Ther(» nro el«7on program oontrolH on oaeh funotlor table, Eaoh program control conalstB of a 
progTsan pulse Input tannlninl fwhlah, wMn atlmulated with » pr'vjr»m pulee, oauaea the program 
control to pro^irara the looking up of « function ?«lue), a program pulse output terminal (which 
•snlta a pulse on completion of tha oppratioo), tha thr»« switohee described below, and an aaBoolete** 
trtinaoel'»er (for neon bulbf> see PX-7"305)» 



Argupwnt reception swl tch 

Itiia switch oporfttefl In oonjunotlon with program pulae output tarmirals WC and and may be 
uned to program «»n acff'imulator or acouraulatora to trannmit the argvunent. 

At tha end of the l»t addition time a program pulse is emitted trtm NC or C if this switch ia 
eot on NC or C reppactivaly. Semi-permanent connections may be eatabliehed by connecting NC ffnd 
C to program input tarminala of the argumsat accumulator and setting the corresponding •pcr«tlon 
switohos to traramlt and transmit-and clear respectively* 



Qpa ration awltoh 

This Bwitch detennlneB whether tha function value (add) or Its complement (subtract J is trans- 
mitted. 

It also determinaa whether the function value of the argument mooived, or the function value of 
one of tha nelRliborlng argumants, is transmitted, Thu? ponitione-2, -1, 0, -H^+g give f(a-2), 
f(a-l), f(a), f{a + l), f(a+2J respectively, where a is the argument. 

Operation repeat aw It eh 

This switch determines the number of tiaaa the function value Is transmitted. 

Note that k addition times are required for the function table to set up, receive the argument, 
etc. This loss of time must be taken account of in programming the accumulator idiich receives the* 
value of the function. Thus if that accumulator is programmod with the same pulse that programa 
the function table with its repeat switch sat to 9, it could receive the. value of the function onlv 
5 tLmes, ' 



Teminals 11, Pi Ill 

Prof^rara pulse input terminals for pm,;ran controls 1-11 rospeotively 

TermiaalB IQ . 2o llo 

Program pulse output teminals for program controls 1-11 respectively 



Tenainal NC 

rrogr«m pulse output terminal apso- 
ciated with NC on argument recoption 
owitch, 

Tenainal Q 

Froijran pulse output terminal asso- 
ciated with C cm argument reception 
switch. 



Time SvJhedulB for Function Table 



Addition time 



(Program input pulae received et end of 0th addition time) 

1 Circuits set up 

2 Arguraant received 

3 Argument modified by the addition of to H pulpas. 
At lUth pulse time portable function table starts 
to set up. 

k Function table finishes setting up 

5 Value of function trancnitted 

r+li Ibis is continued -.ip to the r+Hth addition time, when 

r is tha setting of the f Miction repeat switch, 

(Program output emitted at end of r+Hth ediition tlnwH 



MOORC SCHOOL Of ClCCTRICAi fUGJIItCIIIIC 
UMIVERSrrV of PCWHSViVAIIIA 



nsmm tabll f bomt rarei m i 



AiO^ 'Y=^5'/{f5 



im 



Eer-302 



-tostar HI owUchea 



function output Tanninals- 



yvmotlon output twrmlnala 

Th« dljjlt pul803 r«pra8»ntlng the vulue of th« ftinotlon nro trRnamtttsd from th«i» t^rmlnelfl, A 
'»T>nn<»otlon table snpoarw hiT-^w, TVmoa tarmlBnls bm to M oonnectod to th« digit trunks (tr«y«)' 
(800 ,'X-7-305) by th« digit cables for tmnsraisBlon of ttia fuaotion valuo to another unit nf th« TINIAC. 
It Is to bp notnd that the division of the 'oi^ht oonatont difljit ewltohee and tha 12 funotion tabla 
entries^ into the (/roups A afd 3 waa nn nrbltrsry one, sind by mennH f)f upeclal adnptorn (FX-U-UO) thoea 
can bo raj/roupad in any manner, 

Tabla ahowln« connections of fur^tlon output tarminalp 

Line Temlnal A 



1?! 


;'»uad 




11 m 




10 


(BlllionB 


pln.-^^ 


9 






a 






7 






6 






§ 






3 


(Hundredm 


Plaoe 


2 


{Tens Place) 


1 


(Unltn ri^ca) 




Ground 
1^ 1 

Constant 
Constant 
Const ant 
Constant 
I 



"t^ -S ^' ? 



digit ewHoh k^ 
digit BWltoh A-i 
digit switch AP 
digit switch Al 
'Subtract pul«e awl' oh AlO 
Subtract pulse BwltoJi A9 
Subtract pulse awltoh AC- 
Subtract pulpe swltoh ^7 
iJubtract pulse switch Ab 
Subtract pulrae switch A*-i 



Teminsil B 

Oround 

PM !? 

Constant digit switch 3^' 

Constant digit nwitoh B"^ 

Constant digit switch E^ 

Constant digit switch Bl 



lii 



§ U •£ -9 

r E • s 



Subtract pulse awltoh Bl'' 
subtract oulse switch ¥9 
Subtract pulae switch ll'^ 
Cubtreot pul«e switch B7 
Subtract pulse switch b6 
Subtract pulse Bwltoh B5 



'.llhfn the iiB;lt delate s'rtteh Ib aot to delete the 'jonntant digit switch is disconnected fron its 
function output teTmlnal, nthor*fii='«> it lis left connected. 

Dibits which arfi oanstant for all the Tiiluas of a function may be set up on the constant digit 
switches. 

If these ewitch«8 are "sat to ml or PM2, the outputs of the corresponding niaater PM switches are 
fed througli these awltchop to the output taminals. This feature is used when sotae of the loft hand plaoe»« 
of R runctloa with both positivfj and negative values are zeros; these ewltches then supply zeros when the 
transmitted number la positive and nine's whan the transmitted number Is negative, thvis avoiding the use 
-^^ "'"** * "■- -salving terminals. 



ruhtrnet pulse switch 

on P subtract transmit these nwitchep feed a subtract pulse onto their corresponding function output 
ta-iinal lines if they a?e set to S, Thus the switch corresponding to the units digit of the function 
should be set to S; the others feoding onto the s«me digit tnmk should be set to o» 



sample row of switche. on portable function table 3howin« ocmnection to function output t.eralnals 
Tsnainal A Tevmlnal B 



ATgumattt ' 




Line 6 Line t) Line U Lin^ ? Lin« 2 Line 1 Lin« 6 Line 5 Line U Line 3 Line ? Line 1 ni2 



For a positive n-omber, set, m to p ani set the number on the ewltches. 
ortL^'swlt^hes"""^^''' ^^^ ™ ^' ^'' ^""^ '"^ the complement of the number with respen to Ic^ 



MOORC SCMOOl Of CLCCTilCAt CMCINCftlMC 

UNIVERSITY OF PENNSVIVANIA 



FUNCTION TABLf FROWT PANEL NiaS 



Drawn by: 



a^ 7/v^ 



BC-7-303 



Diagram Showing Ggnl-parmaneat Connoetiona to be Made Between Divider - Gquare - Hooter and its Agaoclated Aecuculato 
$ 






QiOTlEMT 



DIVIDER AND 



aaQPDD 



NUMERATOR 



1 

NUMEOATOR 
flCC3rC*4 3 



JpacfDD 

DENOMINATOR # 



D 
OENOMINflTORJ 




SQ.RflOT/KC 



iQDDDD 






(In dividinc tha 
quotient Is built 
up here. This ace, 
is not used in 
square -root tng, ) 



(The nvureretor or quantity to be 
squere-rooted iK to be plp.cod 
hare.) 



(In dividin<5 the donominntor 
Is to be plHced hare« In 
square rooting twice the 
square root is built up liere,) 



Notes on cables; 




Accunulator interconnecter cable (quotient) (PX-5-l?Hli 

Ace, Intei-connector cable (deiiom.a.K, J (PX-5-136J 

Afc. iPterconnector cable (shift J (PX-5-135) 

Standard digit cable, with adopters fdirider) (PX-^^-ll4) plugged into progpam terminal. 

Standard digit cahle, with adaptors (di\'idor) (PX-H^-ll'tJ plugged into program terminal, 

AGC, intereonnactor cable (divider) (PX-5-1-37) 

Trunk to transmit digit pulses for quotient and square root. 

This trunk is not to be usod for any other purpose » since tlie pulses emitted are not supplied 



I wbich c 



' 9 

I 

SHIFT ACc.I 



fro3 transmitters FutTrom inverter^tuSes which cannot be connected in parallel with anything 
else. These inverters have their own load resistors, so no load box la to be used in connection 
with them. 

Standard digit trunk (with losd bos) using +1 shifter in oC input of the shift accumulator. 
Standard digit trunk transfer (with load box). 



There are eight divider a.quare rooter progrpra controls, each consisting of a program pulse input termlnsl (which, 
when atiraulntod with a program pulse, causes the progrom control to program an operation , in en^crdance with its 
switch settings), a program puisne output terminal (which emits a prograia pulse on completion of the operation, 
including interlocking) the eigJit switches described below, and an associated transceiver (for neon bulbs s«« 
Pa-10-302), 



Number of the program — . 
control to which the 
switch and pulse term- 
inals In a given col'imn 
belong. 



puces O 
- ■" ^7 win 



pEnoMiMTWA((uwiip *wwn<\TORxanroum 



PLACES O 



DENoniwM mmm 



PLACtS Q 

a •* ^ "» on MBO 



DfN6NWT(RA((UHUIJIIK 



PLACES Q 



HOURS ^ 
O , , O 




DtHOWH/treiMqiHUUCT 



PLACES Q 

o '** T -won Hon 



viwmui mmmm 



PUCES Q 

) Qigt ft 



Kvommmnj^^tM 



PLACES O 



'mmmmmm 



PLACES 



^1-0 



'.. 



5. , „. Q 







-Q 






0— : 



°© °@ °© °© °@ t5) °® '© 

'®M '®:®o '®:®o ^:®o °©?©o '®m °<t®o ^^ 



NumeratCir Accumulator Clear Switch 

This governs the clearing of the remainder by means of the static cable running into the numerator accumulato: 
m plug-in unit, if this switch is set on C, the numerator accumulator is cleared of its remainder during the last 
addition time of the division or square root. 



imerator Accumulator Receive Switch 

When semi -permanent corrections are made, this switch programs the numerator accumulator tc 
and ^ digit input terminals during the first addition time of the dividing or square-rooting. 



■eceive on the e£ 



Denominetor -^q uare - Root accuniulator Clear Switch 

This switch operates the same as the numerator accumulato; 
of the denominator-squara-root accumulator. 



clear switch except that it governs the clearing 



Denominator - aquara-Roct Accumulator Receive Switch 

Whan semi -permanent connections aro made, this switch programs the denominator and square root accumulator to 
receive on the o^ and ^ digit input terminals during the first addition time of the dividing or square-rooting, 

tlound-off Switch 

•JKheii let to Ro this switch causes the answer to be rounded off in the last place. 
Note: Bven when the number (s) operated on are such as to give an exact answer this switch must be set to RO to give 
the correct answer, 

Dlvlde - gquare - Root and Places swit eh 
V Thi6 switch eal'ict?; which process is cerrie 1 out and the number of places (counting from the ICth decade, i.e, 

the highest plac«t of the answer, 
Note; The digit answer output tanainal is so wired that the answer is built up starting in the 9th decade (counting 

from the right). For ordinary opemt'.on the numerator (or number to be rooted) and denominator should be placed 
30 thet .th*»re is a in the 10th decade of their accvunulators, if the pumbar to be rooted has en odd (even) 
Lonbar of places to the loft of the decimal point it should be placed so that the left-hand digit 1b in an cfl<! 
(even). numbered decade. Hence the answer will have at least one place lees than the setting of the places 
switch. 



is carried on aimultanenusly with the divi- 

th<9 ciKwcr Bocuuulstor) or square-root In?; 

has b«'?r complHtefJ, a projsran out- 



Tenalnals 11. 2i 



_ lit - Program pulse input terminals for program controls 1-sS respectively. Whan 

stimulated with program pulse causes program control to progr&r;i divl: Ion or squnre-roct in accordance 
with its switch settings, 

TerailnelB ll. 21........ gl - Interlock pulse input torcilual. 

If the interlock switch of a given program control is set et NX, these teminals are net usod. 
If the Interlock switch is s'^t at I, ft pulse must hcve bBon received on a iar interlock taratnal since 
the last non-interlock operation or Initial clearing of the divider before a program output p\ii3e is 
amlttttd. The interlock pulss nBy be a program pulse or a d,i2l* puloo or pulses, 

Teminels lo. go., 



Interlock Switch 

This switch in us'id whenever another operation or set of operatio! 
sion or square-rooting. 

An average division (in ivhich th^re is a zero in the 10th decsi*? 
takes 13p addition tlmee, whare p is the 'setting of the places swltcl.. 

If IntBrlocking is uped, and the Interlock pulse arrives after the opernti 
put pr.lse lf3 emitted durirnr the second ad.il^lon time followin?, 

^swer Dlsposftl s^yjtch 

This svritch r»y b» used to program trensmif?«ion of the quotient or twice the square-root during the first 
addition time foll^vlng the completion of the oparation. The program control output pulse will then be used to 
stiamlate thet unit of the F3JIAC which is to receive thq answer, 

positions 1 and 2 are normally used to govern the quotient accumulator. The operation they perform la deter 
rained by adapter (divider) 



...^0 - progroia pulpo output tomlnalE : 



(PX-1+-11>J-), Thus if PX-'l-lli^A 
is used 

Dlsoosal 1 - Causes quotient 

ace, to add transmit. 
Disposal 2 - Causes quotient 

ace, to add transmit and 

clear. 
Similarly, poaitions 3 and I*' are 
nomally used to govern the de- 
nomdnator-square-root accumulator. 



V yrogrum r;ontrols l-i< respect lvaly«Emltr pro- 
Interlock puloo is received (if interlock 



MOORC SCHOOL OF ELfCTRICAl EMGINCtlllMC 

UMIVERSiTY OF Pfc NNSV IVAfdIA 



DIVIDEP AMD SQUAI^ I^OOTtP TPONT PAMtL 



Ormmrk by: 
J.eDEL?A<l^ 

DEC I9'H 



^mcumi bv 



Aoorov«a Oy: 



PX-10-301 



( 






/Vo 1 0/9^ Sox /s Used O/v 7>/j 
7>P/?K IaJh/ch C^/?/?/s.5 pai.5£^ 



Lj L_J L.J U 

Quotient i-lce. 

r^2 ) 



. j^^ ^ sv ' ' 1 1 r i r I n i I i 
cT] L":i cd c=]__^ i U 1 ! 1 J LJ U L . 



DiV/!DE 



Z)--"^ 



! SOMRRC 



Rooter 






Numerator Acc. j 
v'3 ) 



n □ LI 'Li G 

r] ( Used For20Di^it n 

D Rrdicands) D 

Numerator Rce.E 
(^A ) 



GDUDDDU 

Denominrtor ^ Squrre 
Root Reel ("5 ) 



nLlLiDLTDfJ 

[j(U5FDF0R?0DK.t7[] 
L>LIHQr^lNf«TOr>j 

n n 

Denominator (^jQUPRH 



TTT f .-J- 






[]DnDDL]DilL]DDDD-[lL] 

(lJ5EDfOP20Dl(i, 



5HIFT Reel 



MunfR ATOMS 

Shift Pc: ^^■ 

(*^6 ; 



'~^ D/G/T T/^Ay^i/J iTH /Vo Lo.^D Be 



/r£Ai 


D£sSC/^/pr/o/y \ 


RSIFER To \ 




/) c c u / 7 a L/^ TO ,^ /-y /"^/? c o/^//vs cro,^ T^/R n / /v^ l <5 


px-s-'/os- 


; 


1 

D/y/^£'/9 SL'Sqo^/?^ /9oo7-^^ P/90G.RX^/^/^}//yG 7~£: ff M 1 N /^ L5 


Pa - /o - /Dd 


r^ "^ 


6^^c/^^ Cxi^is Frqi^ ^/g/7" 7"/^/?k To ST/ € 6U/ On Quor/EAjr /^cc. 


PX' T - /34 


: ^ J 


/)/)/g.^ro/?^ Ffi'on SU^ To C/o/r T?,^r O.^r T/^om SUj To O/G/r T^^.'^y 


^ PX- 4 - //4A ^^ /? ^ /^C Adap-o/^ 
-< PA' 4- / /P8.^ X'l t S /iD/9ProR 

lPX-4'//4 C, /:C ^ SC Ad/^pto/^ 

PX- S~ /36, 


!G/ 


S/^£c//Qi C/^Si.d T/^oM D/GrT T/^/^y To ST ^ SU, C/v T/^e Dsa^o/^. ^ Sq. /9oor /}cc. 


i 


S/°^c/AL C/^^^£ /vf^A7 D/G/r T^/9r To ST/ <f SO/ O.v T/vs S^/^r ^'9cc. 


PX - S ' /^s 


1 — , . — , 

I F 


SP£c//yL C.x)BlE T/^of^ SV To ST $ SU/ O^v T^£ /yor-^/Fy^/^ro/^ Ticc, 


PX- P- /32 



i 



3CH00^"LL'CTRiCfiL ENGi!NEERIN( 



iNIVhR5lT 



•Li J 



JNSLVPlNIP 



HSSOCIflTED HC'- 



;i-ia-30/ 



Digit Output Terrnlnol 

.Vher.eTor the traxiOTi.isJon of a -constant is p'^jTrtuivwJ digit pu] '<»3 T^p-rtsontln)? tlile .■ont'tant ar» ensittad from thin teniin-a, TM? tertnlnnl is to b* cowi«ctm\ 
to a digit tninlc (troyj (L>e PX-II-306) by a digit cable for transraipglon or the cops'tant to nco-hsr vinit of thfl I2JiA2. 

A table showing the connecting of thin temlnol for loft-hnnl and ritjht-han.l flv» dli^lt ^;?oup.-., uiirt oorahined loft and riglit-hand ton dlcjit sets, appaar^i below. 
It .nhocld b6 noted thit a left-Land five-digit crtmp would bo received in tb« Iflft-hnnd half of %n ncoumulotor nrxl « ri«ht-hand five-ai(>lt group would ba reaai vad In 
tha right-hand half if no shifter were UFod, 



iQ-dlgit mimber (Ll.) 

ground 
m (of L) 
Billions place 



Hundrods plac*» 
T9U3 place 
'Jnite place 



^ -dlgit left-hand numbor (Lj 

around 
r-ti (of L) 
Ton-thousandths place 



Teas plBO«* 

Unii?8 place 

Nothing 

Nothing 

Kothing 

IJothing 

Kcthing 



^-dl(;lt ri(;ht-hand number jR) 
Ground 

m* (of R) 

FM' (of R) 

i^* iof ni 

Hvl* {of HJ 

rw* {of R) 

Ten-thousandth."? plaea 



Tens plat^e 
Unito place 



*Thu5 w pulfes ar« transcltted on these linea wh-^n the constant is pc-sitiw, § pul«ea wher. it is a oorap]fment, H«Ti.-'f. it ts uano'^e* 
receiving accumulator to i-^jcoive tht« constant Into the units to ten-thousards decades of that acv-uiaulator. 



HEATERS 
OFF Q ON 



O Dig.l MpjlTermw>' O 



MOUK 

CONSTANT 
OTPANSMITTER fs 
^ PANEL I ^ 







tuH °(sia ®a Ha bh °^o 'm. °«^ °^o °@a 

M®o °®B °€|S)o JS@o °©Bo °@^o °@Bo °^o °€® °^&„ 
(S^o °^, °€So "©H ®©o M©o °^ °^^o °^@. °^l^o 



3«naral Explanation of the Constant Trsnsmit'i.er 

The constant transmitter he*: a capacity of 100 dl-jlts and 20 signs. These are divided into 10 seta 

(A, 3, :;, J,K,) each consisting of 10 digitfi and ? signs. £l«ht of these aets (A, 3 G) are supplied 

from IH! cards through th-=i IBL* ruader iirtien proper cornoctions are made on the I3K raade~ plug board (see 
FX-ll-305), Two of those sets (J,:() ere aunplied fr'im the constant sat switches and PW eat swUohes of 
panel 2 (see P:t-ll-303). 

Each sot my be further divided into two groups, a left-hand (zroup and a ri^it-hand group, each oon- 
siatins of fi digita »nA a sisn. This division must renaln fixed thrnu^hout a given set-up. For example, 
if the C set is divided into five-digit groups, then any or all of the cor.stant selector switches 7 to 12 
fany be set tc C. or a but not to Cjj., Conversely, if the T. ?et is not divided, then any or all of the 
constant selector switches I3 tc 1^ .'nay be set to S, ^ but not to E, or S^. 

The im. reader is pro^^rannied from the initiating unit (see PX-9-302). The IBM reader controls and 
plugboard are deBcribed on PX-11-305, 

Constant TranPraitter Prc^^ran Controls 

There are 30 cotistnnt tranaraitter program controls, each capable of transmitting certain of the con- 
f-tnnts over the rUgit output tertiinal , only one program control can be used at a time, hence only one 
number can be transmitted at a time, 

rach progmm control consists of 
1) program pulse input temincl (when 3timu;!ated with program pulse causes program control to program 

t'"'ir,3ri*ssJon of numbor set on its oonptant selector switch) 
9] Constant selector switch 
3) Program pulse output terminal (emits program pulse after constant has been transmitted, i.e., one addition 

time after the program pulse input teminal has received a pulse. 
k) Aspooiated trmscelver (for neon bulb'? seo PX-II-306} 

Program controls I-2U, which transmit constants read from the IBlJl cards, cannot be used during the 
operation of the card reader, except during the first 50 addition times of this operation. That is, after 
a pulse is supplied to Rl on the Initiating unit front panel {see Pa-9-302), these controls may be used 
during the 50 subsequent addition times, but not thereafter until a pulse is emitted from Ho, 



Terminals 11. 21 301 

prn.jram pulse input terminals for pragrari con+rols 1-30 



Terminals 1 , 2 ,. 



sj29 



program pulse output terminals for progra;:; contn^ls I-30 



MOORE SCHOOL OF ELECTRICAL ENGINEERING 
UNIVERSITY OF PENNSYLVANIA 



CONSTANT TRANSMiriLR fPONT PANEL NQl 



Ormmn 






Acrorowsa Oy: 



PX-11-302 



OFF O ^N 



Q 



P 



CD 

CONSTANT 



-'Qi:r.tHqt ij'et owjtchefi for J 
C.Ti;3tar.t. ; et L^yltchep for J, 




'r;«-tin^ Set ;.,Kit;»i-ieR for 



For a po.-iltivo rtiii,ib«r, af-*. tha W. to i f>nd sat the nurabar on tho switches, 
?o~ a rvejratlv** iiumbcir, set »,he iTi to ;»! and net, th" o-ntrplorriant of each di.7rt 
v.'5th r«3P'=*;'t to Q on all but units switch where th« complaraent with 
respect to 10 is a^t. 
For a ten-digit umaber, both PI.: switches should be set to the sign of the number, 



MOORI SCHOOL OF ELECTRICAl EMGiN£ERlNC 
UNIVERSITY OF PtNNSYiyANlA 



CONSTANT T15AN5MlTra TONT PAHEL hD.2 



Drawn d> : 
J.EOELSACK 

DE.C.I944 



Auorovao by : 



PX-tt-303 



^. 



SL. 



(To BeCoNNCcrcD 
lb IBr^ RcADcn) 



INITIAL START SWITCH' 



STOPSWITCH ^ 



-AA 

ONOFr SWITCH 



ojr OH 



CARD 
STftCKER 



Y^ 



1 




Note: l^o not change polarity switch vfcile notor-generator is on. 



Card 

-Stachcr 

Switch 



MOORE SCHOOL Of ELECTRICAL ^'NGi:<iEERIMC 

UMIVERSiTY Of P£ NNSYlVAr^lA 



CON5TA)4T TI^NSMITrEg fOOHT WEL 140.3 



«!;fAuC'' 



JieDElSACK 

DEC. 1944 



,,9H«CK«3 



Aoorotn«a oy ; 



PX-«-304 



The Polarity Cwltoh 

Located on the front of the IBM Reader in a double pole double throw owiteh 
which ohangee the polarity on the holding colls of the relays which control the 
group selection and the reset control. By 9hanglng this switch one can either wire 
these circuits on the plug board in the manner Indicated there or in the jreverse 
manner. This gives the following types of oontroli 

(A) With the polarity switch In nomal position* 

The common terminal "G" is then wirod to some hub of the i^l reading 
brushes and the group selection hubs arn wired to hubs of the digit 
selector. Thus, all controlling Is done by Tarloue punches In one 
column. The variety oi" things controled Is given by plugging to 
different ditjita (12, 11, 0,. ,9) of tho digit soleotor, 

(B) With the polarity switch in abnormal position. 

In this cpse "C is wired to sons digit on the digit solector and the 
group selection hubs are wired to various columns. Here, all the con- 
trol is obtained by a certain punch (for example, a 12 punch) with dif- 
ferent things being controlled by plugging to different columns. 



Plugging Illustrations 

. (a) This shows the comnon hub "C wired to column 21, The two hubs above and 
below C are connected so the wire oould have sous to either of them. Note 
that besides the wire (a) one could connect this upper hub for C to sons 
other column,, say 2, getting an "or* control. That Is, if a certain number 
(12, 11, 0,....,9) Is punched in coluim 21 or column 2 then whatever hub 
under group selection was plugged to that number of the digit selector cauBss 
the coi*responding group .selection relays to operate* 

(b) This wire causes the reset control to operate whenever there is a 12 punch 
In column 21; that is, a card with such a punch is called a master card, 

"(c end d) These lends cause Information in storage relay groups 6 and 7 to be 
held as long as cards coma through without a 12 punch In colunn 21» Tfhen- 
ever a chtA with a 12 punch in colvuan 21 (a master card) cones along the i 
information In groups 6 and 7 will be dropped and new Information will be i\ 
put In from this master card, Imnedlately, the reader will go on to read 
the next card, 

(a) If a card has a 6 pu:iched in column 21 this lead causes group selection 
relays for group 12 to be activated giving a circuit from C through B in- 
stead of A. 

(f and g) If a 9 is punched in column 21 groups I5 and I6 group selection re- 
lays will be activated,' Diagonal leads such as (f) enable one to operpte 
as many groups as desired from Just one punch, 

(h, J, and K) This shows the plugging to handle ten digit negative numbers. 
The PM punch is in column 1 and, by the diagonal connection In the minus 
control, the FM relays for groups 1 and 2 are operated by this one punch. 
The first digit reaches the storafie relays through (j), (k) illustrates 
the plugging for the rest of the digits, 

(n, o, and p) If there is a 6 punch in column 21 the digit from column 20 

will go to the fifth digit of group i. otherwise, the digit from column 
•♦O will go there, 

(m, q, and r) If there is a 9 punch in column 21 the digit In coliunn io will 
be the fifth digit of group 12, otherwise., it will be the fifth digit of 
group 16, 

NOTE: If during the course of e coiaputation tho IBM reader ahould run out of 
cards the starting relay (see FX-11-307) will be closed so the moment new cards 
are dropped In, the reader will go through a cycle. To make sure that tho reader 
does not fall to feed this first card the stop button should be held down until 
the cards are firmly in place. 



— -5 

00000 

85 

-o o o 

' 

, 65 
00000 
PL to 1 HB - Plus t o digit ea l 

o o o I 0/ 



-1^1 Read Bruahea 
0000 

30 
0000 

50 
0000 

70 



■^/ 



1 I I 



Group Selection 

OOOOOOOOOj 

7 i 9 10 n 12 13 Ik 15 ' 

00000 Q^_ O O'^ 

Digit aeleotor ^s^ 6 - f -i 



PL to pesat ahunt - — -4^- Roaat control 

lo 2o 30 »Vo 50 6b JcT io 90 lOo llo 12o I30 iHo I50 I60 





Plug to ST relays 
o 9 o o o 
Plug to 2 RB — 
o C o o 
Plug to ST relays 
o A o o o 
Plug to ST Xttlaiys 

Plug to 2 SB 

O C o « o 

Plug to ST relays 
A o o o 
Plug to ST relays 
o B o o o 

Plug to 2 RB 

o C o o o 
Plug to ST relays 
o A o o o 
Plug to ST relays 




0° 
A o 
o B o 



Group aalAotion- 



o C o 

o A o 

o B o 

o o 

o A o 

o B o 



o C o 
o A o 

o B o 








6 


G 
A 
B 








A 
11 B 







1*1 



A 
B 






C 
A 
B 



- storage Relays 



- Group 6 


- Group 10 
o o 
Group lU 



o o a 
000 
000 



Group 7 

Group 11 - 
o o 
Group 15 



Group 16 



m 



no 



01 Raad Bruabaa 

Tha #1 Raad Bniahaa raad tba card befora tha #2 Raad 
Bruahsa do. Tha ^1 bruahaa are used for oontrol purpoaaa 
and the 4^?. bruabaa for reading tha nunbara and thair pyfa. 

Group SalaotioB 

Tha huta nunberad from ona to aixtean oontrol tha 
group nalection relays whose tamlnals are looatad on tba 
lower half of tha plug board, Thaaa ara double huba, that 
is, tha hub above and below tha numbar ara oonmon. Tha 
siogla hub located to tha left of thaaa and labeled RO 
oontrola the raaat oontrol. The faaturaa of group aalao- 
tion and reset oontrol ara daaoribad below. For detaila 
aaa tha IBU reader wiring diagraa PX-II-II9, 

Raaat Control and Raaat Shunt 

Certain groupa of ral aye (depending upon plug board 
arrangements) may be cauead to hold thair information while 
a sequence of "detail" cards ara read. This ia accwpllahad 
by connecting the corresponding terminala under Reset Con- 
trol to any of the Reset Shunt terminals. To change tha 
information which is being held in these ralaya a "master" 
card is inserted in tha aaquanoe of cards, A particular 
punch on this master card can cauae the held information to 
drop out and as the master card pasaaa tha i^2 Reading Bmshaa 
new infonatlon can be atored in thaaa Relays until tha next 
master card comes along. Whenever such a naater card is read 
the Reader will immediately read the next detail card before 
it gives out a computing signal to tho ENIAC, 
WATNING ; The detail cards either must not contain information 
in the fields corresponding to tha ralaya that ara holding 
BBster card infomation or else group aelectlon must ba uaad 
to prevent such inforoBtion from disturbing the held ralaya, 

Group Selection Relays 

There are sixteen five pole double throw relay awitohaa, 
called the group selection relays. The common terminala ara 
labeled "C" and normally the circuit is through the terminala 
labeled "A", When activated (picked up) the circuit ia 
through »B", These circuits are isolated (Internally) ^rco 
the other circuits of the reader so there are many other 
possible plugging arrangements other than those indicated on 
the plug board. 

Minus Control 

By means of came in the Reader these terminals connect 
to the FM relays of the Constant Transmitter only when tha 
IBM card is in positions 11 and 12, that is, when the PM 
punches would be under the #2 Read Brushes, Tho two hubs, 
above and below the group number, are common. Usually, the 
punch for minus indication will occur in the same column that 
a digit punch appears. Thus, tha some reading brush will 
indicate the PM of the number and later as the positions zero 
to nine pass under the brush Indicate the digit punched. 
Other cams (called coding cams) energize the numerical cir- 
cuits only during tho zero to nine part of the cycle onsbllng 
the dlBjit punch in that column to cause the proper relays to 
be set up in tha Constant Transmitter, The coding cams con- 
sist of two groups, one group Is used for positive numbers 
and the other group causes complements (with respect to 10°-1) 
to be set up by storage relays. The VU relays d9termine which 
sat of coding cams are used. 

Storage Relays 

The storage relays are located in the Conatant Transmitter, 
There are essentially four relays associated with each digit. 
That is, four relays representing respectively 1, 2, 2', and 
H can, in various combinations, represent any digit from zero 
to nine. These four relays are Indirectly (through vacuum 
tube circuits) associated with the 1, 2, 2» , and U pulsop sent 
out by the cycling unit. That is, each relay opens a gate tube 
irtiich through an Inverter opens a second gate tube, Thle 
second gate tube passes the 1, 2, 2* , or 4 pulses. 

For positive numbers the hubs of the #2 reeding brushes 
can be wired directly to tho hubs of the storage relays In any 
order vrtiatsoever. Negative numbers must be handled in groups 
which are multiples of five. To indicate tha negative number 
there will be an 11 or 12 punch in some column. The wire 
from the hub representing this column must go to the minus con- 
trol hubs of sll tho storage relay groups used for this nega- 
tive number. There must also be a connection to the hub cor- 
responding to this digit in tba storage reloys. See the exam- 
ples shown to the left. 



MOORE SCHOOL OF ELECTRICAl ENGINEERING 
UNIVERSITY Of PENNSYLVANIA 



/^ /P<r/7Z?^^ /^/^^ So/?J^a 



± 



Drawn Oy 1 

J. C^U^ niK/^S 



/2- 7- ^S'(f 



Aoorovoo oy : 



PX-U'JOS 




' poaltlon. It provides for 



T:iB 5iwltoh icuj-les tw^-^ iirfour's of digits together when it is set 1 
thtf ''»rryo*?6r when ar SNIAC conplenent is converted to a true vnlue. 

riio switches or this 'irawln*^ and rX-12-303 ar« sflt for the Brrnngement ahovm In th« tabl« below, 

T'ible i'howiiiR Cricrins.! Sot f^T D«icBd«s Connected to the Printer 



Moflter ProgramiD 


•»r, Fen^l 1, r 




lU 


-l^ 




Ac",>u!En1ptor 


1'^. 


T'ecadoE 


6-10 


Acoumulstor 


1^. 


i)ec8des 


!-« 


A^cijpuJatoT 


l^, 


r^^oadep 


6-JO 


ACiurrmlPtor 


l"*. 


OecadAP 


l--: 


Accur!u]ator 


l^i, 


Decadas 


6-10 


A'^cumulfitor 


16, 


liecades 


6-10 


AccumuTator 


16, 


J» cades 


i-K 


Accumulator 


17, 


Tecftdea 


6-lc 


Accumulator 


37. 


Decades 


1-^ 


Accumulator 


1><, 


Decades 


fa-10 


Accumulator 


If?, 


Decades 


1.-^ 


Aocunulator 


19, 


Decades 


6-10 


Accumulator 


1"^. 


Decnde.i 


1-5 


Accumulator 


20, 


Decides 


6-lc 


Accumulator 


2C, 


Decades 


3-5. 



MOORf SCHOOL OF EtfClRKAl fNGIWeH^NC 
UNIVIRSIIY Of Pr N'>>> I VflNIA 



?mm fmipmii kio.i 



Drawn d> : 
J.Ct>ELS|<K 






40Uruv«fO oy; 



PX-i2-30l 



J 






i^im^sm^s^ 



Creneml Sxplen&tlon of Prlntar 

The printer oparntos from the statin outputs of accumulator and muster progranimer decadec. 
The cables connecting the decade static temlnBle to the printer llo in e trough at the top of 
the front of the suichine. A table, shoving; the original ftet of connections, appears on PX-]2-30.1, 
Kvery accumulPtor decade and PU unit and every master programraer decade has a fltatio output term-* 

The numborp to be printed am divided into sixteen groups of >, digits and a m, numbered 
from 1 to 16. The printing switches determine which groups are connected to the IBM gang punch. 
Drawing ?.s;-lP-305 Bhows the I3M gang punch plug board and gives instructions for connecting it up. 

Any group of fiv> dlf?itfl and a I>1.; may be connected to an adjacent group bv means of the 
coupling switch, so that ]0 digit, If; digit, etc. nunbers may be punched. 

vni«ui tli^ mirab<ir to b'j printed is n complement (i.e., the n/ counter retflstare u), the true 
valua of the number Ik punched along with an 11 punch to indicate that it is 'negative, 

:>hanHver info-~r-ition In the mnster nrognwnmer is printed adaptor P}:-l!?-lll| B muFt be used 
et the printer pluw;? on panel ?. so as to ground the umi?ed TM lead going into the printer. 

The printer U progrmamed from the iritlating unit (see P.'.-9-30?). Controls on the I3t; gene 
puiiQh'are explained on PX-lP-30?. 



oj^tQoh 



3 



4- 

OrF PBNT 



|5 

OfFWlNT 



7 

OTf fWNT 



6 

Off nm 



I8.M. 

tloBcCMMECTCPTb 



O WNtLA O 



12 

Opr PRINT 



13 

OFF PRJNT 



14 

Off PWKT 



OFF fftl^T 



CFP HUNT 






ThiB switch conT)ecte (in the "print" position) or disconnects (in the "off" position) the voltage 
■5''PP-y ^-^ the buffer tubes of its group, sc that these tubes do (or do not) operate the relays when the 
printer i'? rro--rRmned. For the (^roup of digits to bo punched it is necessary not only that this switch 
be set to nPrint" but fjlso that proppr connections be mode on the IBIvl gan^ punch plug board (see rX-]2-305). 

"ails F-A'iteb mriEt be turned off if the decedee to which the group is connected are not turned on. 



Master DETftit 5wito4_ 
flLwwvs 5rr ToTIrster' 




MOORI SCHOOL Of CllCT»KAi IHCIHtlilllt 
Um vCtStTY 01 MNHIViUHIA 



PRlNTLg fl^QKT PANLL_}«,i 



Ofswn ton: 
aEDELSACK 

DEC. 1944 



a^c. i////j^ 



^\ 



Rtl2-302 































O PRINTER 

PANEL 3 
O 




























9-10 




lO-ll 




11-12 




12-13 




- Ccup^ i'v switch 




w^ 




:i'if Ea-l?-30Ti for en e.-q'lar.ftt.tcrj 
of thle switoh 




l 
3 ^ 


















13-14 




14-15 




15-16 




16-1 






















MOORE SCHOOL Of etCCTRICAL tNGINHRfNC 

UNivtRsnv or pennsylv/<ma 


PPINTCB fBONT PANEL N0.3 


MATERIA^ 


: -NiitM 










Df»wn o>; 
DtC.1944 




«Ouru««a Oy: 


PXi2-303 















Computer Hosult Sxlt 

These hubs connect directly to the digit relays in the printer. To 
punch positive numbers they can be plugged to the punch megnet hubs in 
any desired arrangement. Thus, it is possible to place the digits coming 
from the group 1 relays in any five of the eiglity columns on the IBM 



Minus Indication, 

The sixteen hubs under minus indication go directly to the FM relays 
of the sixteen groups, Itio minus indication of any jroup could be punched 
in any of eighty columns on the card simply by connecting the corresponding 
minus indication hub with the particular column hub of the punch magnets. 

Usually, however, the minus indication will appear above some digit 
of the number on the card. To place the minus indication (an 11 punch) 
above the first digit of the number the minus indication of the correspond- 
ing group is plugged to one of the terminals labeled "A" under column splits. 
The hubs "B" and "C directly under the A-hub used are to be plugged, respect- 
ively, to the digit hub (comuter Results Exit) above irtiich the minus punch 
is desired and to the corresponding hub of the punch magnets. 

The column splits is simply a sixteen pole double throw relay switch. 
This switch is controlled by a can in the IBM punch »rtilch causes the "c" hubs 
to be connected to the respective "A" hubs during the 11 position of the card 
and to the "3" hubs during the 0,,,..,,9 position of the card, 

Kmitter Outputs 

If one of these hubs is plugged to a punch raagnet hub the corresponding 
number will be punched in that column of the card. The five rows of five 
conmon hubs to the right of the emitter outputs enable one to punch the same 
number in more than three columns. The connection labeled (o) on the diagram 

causes nines to be punched in the columns 77 ,J?0 on the card, connections 

such as these cause the corresponding number to bo punched in every card. 
This can be ueed to f»ivB identifying numbers to the cards or to punch dates on 
the cards. Alphabetic punching cannot be done on this machine. 




PITTO BOARD FOR GANG P^BCH 

Computer Result Exit- 

o o o j o o <J 

Group 6 . Group 7 

o o o o o o 

Group 10 ; Group 11 

> o o O j O o 

Group Ik orw«) 15 




lation 

O 

Column Splits 


10 
o 




11 

o 




-12 
o 

o 


-13 - 
o 




-14 - 

o 


-15 
o 


-16 - 
o 


coo 


o 


o 











o 














o o o 


o 


o 





° 


6 


o 


o 



Punch Magnets - 



±d±d 



Plugging Illustrations 

(a) This illustrates the type of plugging In columns where no 
minus indication is desired, 

(b, c, end d) When the 11 position of the card is under the 
punches there is a connection through leads (c) and (d) 
from the punch magnet hub to the minus Indication, If 
the group 1 PM relays were activated a signal will arrive 
at this time causing the 11 to be punched in column 1 on 
the card. If the 11 punch indiceting a negative number 
were desired in column 2 leads (a) end (c) must be inter- 
changed at the punch magnet hubs and leads (a) and (d) 
interchanged at the computer exit hubs. Then the first 
column of the computer exit cooes directly to the first 
coliunn punch and the second column leads go through the 
minus indication hubs and the column split, 

(e) These connections will cause nines to be punched in the 
last four columns on the card. 



MOORE SCHOOL Of ELECTRICAL ENGINEERING 
UNIVERSITY Of PENNSYLVANIA 



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General Bzplanatlon of Steppers wnd Decades 

A stepper is a six stegw ring counter. It has the following asaociated with it; 

1) Stepper program pulae input terminal 

2) Six st3pper program pulse output terminals, one aBSOciated with each stage of the 
stepper. 

3) A group of decades (of from to 5, depending upon the stepper and the settings of 
the decade associator switches. The n (nS0,,,.,,5) decades of each group are Inter- 
connected by a direct carry-over circuit (*->>»t«» Is no delayed carry-OTer circuit) 
enabling them to count (not accunulatt) 10-1 pulses, 

k) Stopper clear switch 

5) Stepper direct input terminal 

6) Stepper clear direct input terminal 

7) Each decade has a direct input terminal 

The operation of a stepper and its associated equipment is as follows: 

At the end of the initial clear each stepper is left or the Ist stage and each decade 
is cleared to 0. 

Suppose a program pulse is received on a stepper program pulse input terminal. One 
addition time later a program pulse is emitted from the proc^ram pulse output terminal cor- 
responding to the stage the stepper is on at the time it is emitted and a program pulae is 
sent to the units decade of the group of associated (facades, 

TJhenaver a group of decades counts to the number set on those decade switches corre- 
sponding to the position of the stepper, one addition time later these decades are cleared 
to zero and the stepper is either stepped to the next position, or (if It la on the position 
sat on its stepper clear switch) cleared to the first position. Though the decades will 
count either program pulses or digit pulses, any pulse which might cause this clearing and 
stepping action must be a program pulse. 

The decades count both the pulses supplied to the associated stepper's program pulse 
input terminal (with a one addition time delay) and those supplied to the decade direct 
input terminals. No set-up is permissible which might lead to pulses being supplied to a 
decade from both sources simultaneously, or from a decade direct input terminal and a carry- 
over from a previous decade siraultsnoously. 

An example Illustrating a common application of a stepper in programming will show how 
items 1 through k operate together. Consider stepper D, and suppose that decades 12 and 13 
are Bssoclated with it and that its stepper clear switch is set to \, Then four two-digit 

numbers (nj^ nlj) may be sat up on the decade switches, each number associated with the 

corresponding stage (1 14-) of the stepper and hence with the corresponding program pulse 

output terminals {D]_o, Q^oJ, Whenever a program pulae is received on d£ a pulse is 

emitted from one of the output teminals (one addition time later). The first n-^ pulses 
received on Di are emitted from D^o; the next n2 pulses received on D^ are emitted from Dgo,,. 
,,,, the last nij. pulses received on Dj are emitted from Dl^o, aijd the stepper and its asso- 
ciated decades are then left in their original state, ready to repeat the process. The time 
schedule of these operations in as follows: 

Program pulse operation 

Input program pulse (to Di) 

1 Output program pulse emitted (from Dio,,,,Dlj.o) 
Decade stepped to next stage 

? In case the decades register the number net up on 

the decade switches, all decades (associated with 
stepper D) ore clBered to z'jro end the stepper (£») 
is stepped to the next stage or (if it is on the 
position ^) it 1"? cleared to the first stage. 



Stepper terminals 

Ai,,,,,,,,»Ki Stepper program pulse input terminals 
AiO,,.,,,A6o;,,Kj^o,,,,Kgo Stepper program pulse output terminals 

Aai,....,Kdl stepper direct input terminals 

Acdl,.,,,Kcdl Stepper clear direct input teminals 

Decade terminals 

Ddi20,,,,,Ddll Docado direct input terminals 



To disassociate a decade from Its stepper pull 
Sea block diagram P:C-^-30*^. 



lut gate tube 63 in the stepper plug-in unit. 



Terntnala Ai. Bl Ki Stepper prograir puis? input terminal b 

Terminals A ^ o K jO Stepper program pulse outout terminals associated 

with Stage 1 

AgO .Kpe Stage 2 

A50 %. Stage 6 

one addlt.ion time after a program pulse is supplied to an input terminal (such as Di) 
a program pulse Is emitted from the output terminal corresponding to the stege the stepper is on 
at the time it is emitted (thus if the stepper la at position 4, whan the pulse 1« emitted it 
comes from D^o), and a unit is addea to the contents of the associated decades, 

Tormlnais Acdj Kcdi Stepper clear direct Input terminals. 

A pulse supplied to this terminal will clear the stepper to the first oosltlon. If a 
clearing pulse and a stepping puls« arrive at the same tirar, the stepper will be cleared, not 
stepped. 



Hi 



MOOftC SCHOOL OF ElECTtlCAL CMCINICiINC 
UMIVERSITY Of PEMMSVIVAMU 



MASTER PPQGRAMMER FTOKJT PAWEL NO.i 



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TETMINALS Idl, 2dl, ..«.,,20dl - Decade direct input terminals iL330ciated respactivaly with decades 1, 2,....,?0. 
(counted from riglit to X^tt] 

Pulses supplied to these terminals will be counted by the decades. Those pulses may be either program, or digit 
pulses, though any pulse *rtiioh steps the decades to the number sat up on the decade switches corresponding to poeition 
of the stepper must be a program pulse., and any pulse »^iich causes a carry-over rmnt be a program pulse, 

Ko program pulse should be supplied to the decade direct input of the units decade of a stepper oao addition 
tine following the reception of a program pulse on the program pulse input terminal of that stepper. 

Pulses can be fed into the diruct input temiaals of decades other than the units decade only at times when thare 
are no carry-over pulses from previous dacad-js of the get. 



To dlH«anooiat» a decade frcm its atappar pull ov>t gat» tubu 65 In thu ateppar plug-in 
unit - r>ee Block Diagram TX-MoH. 



D«oidw Asaoojator Swltoh»» 

Daoadaa provided with thaaa awttohoa may ba oonnaoted to tht daoadct •••oolatad with tlthar of two 
^ stappors. Thus If the J-K swltoh la aet to K| daoada 2 la ooBnaotad In aarlaa with daoad* 1, whUa If It 
' la sat to J daoade 2 ta raada the unlta daoada aa'aooiatad with atappar J, and daoada 3 (fornarly tha unlta 

daoAda aaanolatad with that atappar) becomes tha tana daoade of that atappar, l«e,, la put In aerlea idth 

daoada 2, 



Daoada swltehos nsaoeiated with the lat atagaa of tha atappara. 



^ Decade switches assoolatad with the 2nd atagea of tha ateppera. 



. Qecade swltchea associated with tha 3rd staees of tha atappara. 



, Decade switches assoolatad with tha llth atagea of tha ateppera. 



. Decade switches associated with the 5th stages of tha steppers. 



Decade switches associated with the 6th stages of the steppers. 



- Ste pper clear switch 

Tbis switch determines the number of stages of the stepper and associated decade switches irtilfih are 
used. After the stepper gets to the stage set on its clear switch a^nS counts to the number aet on the 
corresponding decade switches it clears to its first position instead of stepping to the next position* 

Terminals Adl. Kdl - Stepper direct input terminals. 

Pulses supplied to one of these terminals will be counted by tha stepper. These pulaes mey be either 
program pulses or digit pulses. If digit pulses are used the stepper clear switah must be aet to 6« 

Tha stepper will count modulo c, where c is the setting of the stepper clear switch, 

A program pulse is emitted from one of the stepper program pulse output tennlnala one addition time 
after a program pulse is received on the stepper program pulse input tanninal , This pulse is emitted from 
tha terminal corresponding to the state of the stepper at tha time it is emitted, Tha stepper may be stepped 
or oleayad at the same tims without effecting that pulse. 

No pulse should be supplied to this terminal at the same time as a Ptepplng action Is caused by tha 



MOORC SCHOOL OF ELECTfflCAl CNGIIIiCIIIMC 
UNIVERSITY OF PENNSYLVANIA 



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DEC. 194^ 



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MOORf SCHOOL Of ELfCTRICAl ENGINEERING 
UNIVERSITY 0^ PtNNSYlVANU 



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